I felt ill at ease in such formal clothes.

我穿着这样正式的衣服觉得很拘谨。

《牛津词典》

Students are supposed to wear formal clothes at the prom.

学生们在毕业舞会上应该穿正式的衣服。

youdao

youdao

Welcoming his guest in formal clothes with a lantern, the farmer allows it to rest in a guest room before assisting it with a bath and offering a meal of rice, beans and fish.

UNESCO: Culture

In the past, all lawyers appearing before the Court wore formal "morning clothes, " but today only federal government lawyers carry on the tradition.

CNN: The U.S. Supreme Court: How it works